Answer: 

Grease term is used to describe semisolid lubricants. It is a proportional combination of lubricating fluid, performance enhancing additives, and thickener. The lubricating fluid or oil is the main component which consists of aproximately 75% of grease and it is held in place by gel structure of thickner.

The conditions in which greases are used are:

• Machinery that is not easily accecible for frequent lubrication e.g. sealed electric motors and gearboxes.
• Machinery which operate under high temperature and pressures, shock load, slow speed and heavy load.
• Worn parts in machines can be maintained for longer time by using thick film of grease.
• Machines which are used intermittently or not used regularly as grease remaines in place for long period of times.